Chris@0: <?php
Chris@0: 
Chris@0: namespace PhpParser;
Chris@0: 
Chris@0: class NodeTraverser implements NodeTraverserInterface
Chris@0: {
Chris@0:     /**
Chris@0:      * If NodeVisitor::enterNode() returns DONT_TRAVERSE_CHILDREN, child nodes
Chris@0:      * of the current node will not be traversed for any visitors.
Chris@0:      *
Chris@0:      * For subsequent visitors enterNode() will still be called on the current
Chris@0:      * node and leaveNode() will also be invoked for the current node.
Chris@0:      */
Chris@0:     const DONT_TRAVERSE_CHILDREN = 1;
Chris@0: 
Chris@0:     /**
Chris@0:      * If NodeVisitor::enterNode() or NodeVisitor::leaveNode() returns
Chris@0:      * STOP_TRAVERSAL, traversal is aborted.
Chris@0:      *
Chris@0:      * The afterTraverse() method will still be invoked.
Chris@0:      */
Chris@0:     const STOP_TRAVERSAL = 2;
Chris@0: 
Chris@0:     /**
Chris@0:      * If NodeVisitor::leaveNode() returns REMOVE_NODE for a node that occurs
Chris@0:      * in an array, it will be removed from the array.
Chris@0:      *
Chris@0:      * For subsequent visitors leaveNode() will still be invoked for the
Chris@0:      * removed node.
Chris@0:      */
Chris@0:     const REMOVE_NODE = false;
Chris@0: 
Chris@0:     /** @var NodeVisitor[] Visitors */
Chris@0:     protected $visitors;
Chris@0: 
Chris@0:     /** @var bool Whether traversal should be stopped */
Chris@0:     protected $stopTraversal;
Chris@0: 
Chris@0:     /**
Chris@0:      * Constructs a node traverser.
Chris@0:      */
Chris@0:     public function __construct() {
Chris@0:         $this->visitors = array();
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Adds a visitor.
Chris@0:      *
Chris@0:      * @param NodeVisitor $visitor Visitor to add
Chris@0:      */
Chris@0:     public function addVisitor(NodeVisitor $visitor) {
Chris@0:         $this->visitors[] = $visitor;
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Removes an added visitor.
Chris@0:      *
Chris@0:      * @param NodeVisitor $visitor
Chris@0:      */
Chris@0:     public function removeVisitor(NodeVisitor $visitor) {
Chris@0:         foreach ($this->visitors as $index => $storedVisitor) {
Chris@0:             if ($storedVisitor === $visitor) {
Chris@0:                 unset($this->visitors[$index]);
Chris@0:                 break;
Chris@0:             }
Chris@0:         }
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Traverses an array of nodes using the registered visitors.
Chris@0:      *
Chris@0:      * @param Node[] $nodes Array of nodes
Chris@0:      *
Chris@0:      * @return Node[] Traversed array of nodes
Chris@0:      */
Chris@0:     public function traverse(array $nodes) {
Chris@0:         $this->stopTraversal = false;
Chris@0: 
Chris@0:         foreach ($this->visitors as $visitor) {
Chris@0:             if (null !== $return = $visitor->beforeTraverse($nodes)) {
Chris@0:                 $nodes = $return;
Chris@0:             }
Chris@0:         }
Chris@0: 
Chris@0:         $nodes = $this->traverseArray($nodes);
Chris@0: 
Chris@0:         foreach ($this->visitors as $visitor) {
Chris@0:             if (null !== $return = $visitor->afterTraverse($nodes)) {
Chris@0:                 $nodes = $return;
Chris@0:             }
Chris@0:         }
Chris@0: 
Chris@0:         return $nodes;
Chris@0:     }
Chris@0: 
Chris@0:     protected function traverseNode(Node $node) {
Chris@0:         foreach ($node->getSubNodeNames() as $name) {
Chris@0:             $subNode =& $node->$name;
Chris@0: 
Chris@0:             if (is_array($subNode)) {
Chris@0:                 $subNode = $this->traverseArray($subNode);
Chris@0:                 if ($this->stopTraversal) {
Chris@0:                     break;
Chris@0:                 }
Chris@0:             } elseif ($subNode instanceof Node) {
Chris@0:                 $traverseChildren = true;
Chris@0:                 foreach ($this->visitors as $visitor) {
Chris@0:                     $return = $visitor->enterNode($subNode);
Chris@0:                     if (self::DONT_TRAVERSE_CHILDREN === $return) {
Chris@0:                         $traverseChildren = false;
Chris@0:                     } else if (self::STOP_TRAVERSAL === $return) {
Chris@0:                         $this->stopTraversal = true;
Chris@0:                         break 2;
Chris@0:                     } else if (null !== $return) {
Chris@0:                         $subNode = $return;
Chris@0:                     }
Chris@0:                 }
Chris@0: 
Chris@0:                 if ($traverseChildren) {
Chris@0:                     $subNode = $this->traverseNode($subNode);
Chris@0:                     if ($this->stopTraversal) {
Chris@0:                         break;
Chris@0:                     }
Chris@0:                 }
Chris@0: 
Chris@0:                 foreach ($this->visitors as $visitor) {
Chris@0:                     $return = $visitor->leaveNode($subNode);
Chris@0:                     if (self::STOP_TRAVERSAL === $return) {
Chris@0:                         $this->stopTraversal = true;
Chris@0:                         break 2;
Chris@0:                     } else if (null !== $return) {
Chris@0:                         if (is_array($return)) {
Chris@0:                             throw new \LogicException(
Chris@0:                                 'leaveNode() may only return an array ' .
Chris@0:                                 'if the parent structure is an array'
Chris@0:                             );
Chris@0:                         }
Chris@0:                         $subNode = $return;
Chris@0:                     }
Chris@0:                 }
Chris@0:             }
Chris@0:         }
Chris@0: 
Chris@0:         return $node;
Chris@0:     }
Chris@0: 
Chris@0:     protected function traverseArray(array $nodes) {
Chris@0:         $doNodes = array();
Chris@0: 
Chris@0:         foreach ($nodes as $i => &$node) {
Chris@0:             if (is_array($node)) {
Chris@0:                 $node = $this->traverseArray($node);
Chris@0:                 if ($this->stopTraversal) {
Chris@0:                     break;
Chris@0:                 }
Chris@0:             } elseif ($node instanceof Node) {
Chris@0:                 $traverseChildren = true;
Chris@0:                 foreach ($this->visitors as $visitor) {
Chris@0:                     $return = $visitor->enterNode($node);
Chris@0:                     if (self::DONT_TRAVERSE_CHILDREN === $return) {
Chris@0:                         $traverseChildren = false;
Chris@0:                     } else if (self::STOP_TRAVERSAL === $return) {
Chris@0:                         $this->stopTraversal = true;
Chris@0:                         break 2;
Chris@0:                     } else if (null !== $return) {
Chris@0:                         $node = $return;
Chris@0:                     }
Chris@0:                 }
Chris@0: 
Chris@0:                 if ($traverseChildren) {
Chris@0:                     $node = $this->traverseNode($node);
Chris@0:                     if ($this->stopTraversal) {
Chris@0:                         break;
Chris@0:                     }
Chris@0:                 }
Chris@0: 
Chris@0:                 foreach ($this->visitors as $visitor) {
Chris@0:                     $return = $visitor->leaveNode($node);
Chris@0: 
Chris@0:                     if (self::REMOVE_NODE === $return) {
Chris@0:                         $doNodes[] = array($i, array());
Chris@0:                         break;
Chris@0:                     } else if (self::STOP_TRAVERSAL === $return) {
Chris@0:                         $this->stopTraversal = true;
Chris@0:                         break 2;
Chris@0:                     } elseif (is_array($return)) {
Chris@0:                         $doNodes[] = array($i, $return);
Chris@0:                         break;
Chris@0:                     } elseif (null !== $return) {
Chris@0:                         $node = $return;
Chris@0:                     }
Chris@0:                 }
Chris@0:             }
Chris@0:         }
Chris@0: 
Chris@0:         if (!empty($doNodes)) {
Chris@0:             while (list($i, $replace) = array_pop($doNodes)) {
Chris@0:                 array_splice($nodes, $i, 1, $replace);
Chris@0:             }
Chris@0:         }
Chris@0: 
Chris@0:         return $nodes;
Chris@0:     }
Chris@0: }